Description:

This Multi-Processing Module (MPM) implements a non-threaded,
pre-forking web server that handles requests in a manner similar
to Apache 1.3. It is appropriate for sites that need to avoid
threading for compatibility with non-thread-safe libraries. It is
also the best MPM for isolating each request, so that a problem
with a single request will not affect any other.

This MPM is very self-regulating, so it is rarely necessary to
adjust its configuration directives. Most important is that
MaxClients be big enough to handle as many simultaneous requests
as you expect to receive, but small enough to assure that there
is enough physical RAM for all processes.

Check for available Apache modules here: http://nux.se/apache/